The rule
Choose the measure that answers the question: how many times the behavior occurs, how long it lasts, how long it takes to begin, or how long the gap is between responses.
First identify exactly what counts as the behavior. For a time measure, identify the event that starts the clock and the event that stops it. Use those events to select the timestamps needed for the requested measure.
Key terms
- Operational definition
- The observable rule specifying exactly which actions count as the behavior.
Worked examples
Frequency
Count the occurrences
During a 20-second observation, the RBT counts desk taps. One tap means the learner's fingertip contacts the desk and then lifts clear. The learner makes five separate taps, at seconds 2, 5, 9, 13 and 17, with no other taps. The requested measure is the number of taps during the observation.
Relevant facts
- Five separate contacts meet the tap definition.
- The request asks for the number of taps.
Use frequency: 5 taps.
1 + 1 + 1 + 1 + 1 = 5 taps
Each defined occurrence contributes one to the count. Count the taps within the 20-second observation. To calculate rate, divide that count by the observation time.
Duration
Add the time spent doing the behavior
The RBT records hand-raising during a 90-second observation. A raised-hand episode begins when the learner's wrist moves above shoulder height and ends when it returns to shoulder height or below. The wrist is above shoulder height from second 12 to second 27, then from second 45 to second 65, and at no other time. The request is for total time with the hand raised.
Relevant facts
- The first episode lasts from 12 to 27 seconds.
- The second lasts from 45 to 65 seconds; the hand is lowered between episodes.
Use total duration: 35 seconds.
(27 − 12) + (65 − 45) = 15 + 20 = 35 seconds
Time each episode from its start to its end, then add the episode lengths. Counting two episodes would give frequency. Timing from the first onset to the final offset would incorrectly include the time with the hand lowered.
Latency
Time the wait before the response starts
The written recording procedure starts timing when the instruction is complete. The RBT finishes saying “Squeeze the foam ball” at 9:20:10. The learner reaches for it at 9:20:13, visibly compresses it at 9:20:16, and keeps it compressed until it returns to its original shape at 9:20:35. Squeezing begins when the ball visibly compresses and ends when it returns to its original shape. The request is for the delay before squeezing begins.
Relevant facts
- Instruction complete: 9:20:10.
- Defined squeezing response begins: 9:20:16.
Use latency: 6 seconds.
16 − 10 = 6 seconds
The clock runs from the specified instruction endpoint to the first visible compression. Reaching for the ball occurs within that waiting period. Compression starts the response and ends the latency interval.
Interresponse time (IRT)
Measure the gap between two responses
The RBT records separate bell-ringing episodes. An episode starts when the learner begins shaking a handbell and ends when the learner stops moving it. The first episode runs from second 4 to second 9. The next begins at second 23, with no bell-shaking between them. The request is for the time from the end of the first episode to the start of the next.
Relevant facts
- First episode ends: second 9.
- Next episode begins: second 23.
Use interresponse time: 14 seconds.
23 − 9 = 14 seconds
Measure the gap from the end of the first episode to the start of the next. Episode duration runs from shaking onset to shaking offset. Latency runs from a specified cue or instruction to the response.
Reviewed 2026-09-30 · A.1 version 3.